Jan 4, 2013

Highly Variable El Niño–Southern Oscillation Throughout the Holocene

Kim M. Cobb, Niko Westphal, Hussein R. Sayani, Jordan T. Watson, Emanuele Di Lorenzo, H. Cheng, R. L. Edwards, Christopher D. Charles
  • States that the sensitivity of the El Niño–Southern Oscillation (ENSO) to continued anthropogenic greenhouse forcing is uncertain
  • Analyzes fossil coral reconstructions of ENSO spanning the past 7000 years from the Northern Line Islands, located in the center of action for ENSO
  • Shows that corals document highly variable ENSO activity, with no evidence for a systematic trend in ENSO variance, which is contrary to some models that exhibit a response to insolation forcing over this same period
  • Finds that twentieth-century ENSO variance is significantly higher than average fossil coral ENSO variance but is not unprecedented
  • Results suggest that forced changes in ENSO, whether natural or anthropogenic, may be difficult to detect against a background of large internal variability